LT1269CSW#PBF [Linear]
LT1269 - 4A High Efficiency Switching Regulators; Package: SO; Pins: 20; Temperature Range: 0°C to 70°C;
| 型号： | LT1269CSW#PBF |
| 厂家： | 
Linear |
| 描述： | LT1269 - 4A High Efficiency Switching Regulators; Package: SO; Pins: 20; Temperature Range: 0°C to 70°C 稳压器 开关 |
| 文件： | 总8页 (文件大小：216K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT1271/LT1269
4A High Efficiency
Switching Regulators
U
DESCRIPTIO
EATURE
S
F
■
■
■
■
■
■
■
■
■
Wide Input Voltage Range 3.5V to 30V
Low Quiescent Current: 7mA
The LT®1271 and LT1269 are monolithic high power
switching regulators. Identical to the popular LT1070,
except for switching frequency (LT1271 = 60kHz, LT1269
= 100kHz) and slightly lower switch current, they can be
operated in all standard switching configurations includ-
ingbuck, boost, flybackandinverting. Ahighcurrent, high
efficiency switch is included on the die along with all
oscillator, control and protection circuitry. Integration of
all functions allows the LT1271/LT1269 to be built in a
Internal 4A Switch
Very Few External Parts Required
Self Protected Against Overloads
Shutdown Mode Draws Only 100µA Supply Current
Flyback Regulated Mode Has Fully Floating Outputs
Comes in Standard 5-Pin Package
Can Be ExternallyO SyU nchronized (See LT1072 Data Sheet) standard TO-220 power package. This makes them ex-
PPLICATI
S
A
tremely easy to use and provides “bust proof” operation
similar to that obtained with 3-pin linear regulators.
■
Boost Converter
■
High Efficiency Buck Converter
PC Power Supply with Multiple Outputs
Battery Up-Converter
The LT1271/LT1269 operate with supply voltages from
3.5V to 30V, and draw only 7mA quiescent current. By
utilizing current mode switching techniques, they pro-
vides excellent AC and DC load and line regulation.
■
■
■
Negative-to-Positive Converter
USER NOTE:
A patented adaptive antisat switch drive allows very wide
ranging load currents with no loss in efficiency. An exter-
nally activated shutdown mode reduces total supply cur-
rent to 100µA typical for standby operation.
This data sheet is only intended to provide specifications, graphs, and a general functional
description of the LT1271/LT1269. Application circuits are included to show the capability of the
LT1271/LT1269. Acompletedesignmanual(AN-19)shouldbeobtainedtoassistindevelopingnew
designs. This manual contains a comprehensive discussion of both the LT1070 and the external
components used with it, as well as complete formulas for calculating the values of these
components. The manual can also be used for the LT1271/LT1269 by factoring in the higher switch
current rating and higher operating frequency.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a trademark of Linear Technology Corporation.
U
TYPICAL APPLICATION
High Efficiency 5V Regulator with Burst ModeTM Operation
Maximum Output Power
50
V
IN
6.5V TO 25V
V
V
SW
IN
BOOST
BUCK-BOOST
= 12V
40
30
V
O
LT1271
EFFICIENCY
OUT
≈ 90%
(INVERTING)
AT I = 0.4A TO 1.5A
FB
V
C
GND
FLYBACK†
1N4148
0.02µF
680Ω
0.1µF
20
L1
+
4.7µF
0.03µF
25µH
TANT
TO 50µH
BUCK-BOOST
0.015Ω
10
0
V
OUT
5V, 3A
V
= 5V
O
(INVERTING)
MBR
330pF
+
390µF
16V
0
5
15
20
25
30
10
INPUT VOLTAGE (V)
+
V
C
DIODE
V
1271/69 TA02
V
V
LIM
BUCK MODE OUTPUT POWER
≈
(3.5A)(V
)
OUT
IN
+
C1
†TRANSFORMER TURNS RATIO MUST BE
OPTIMUM TO ACHIEVE FULL POWER.
LT1432
GND
200µF
V
OUT
35V
MODE
<0.3V = NORMAL RUN MODE
>2.5V = SHUTDOWN
OPEN = BURST MODE OPERATION
127/691 TA01
1
LT1271/LT1269
W W W
U
ABSOLUTE AXI U RATI GS
Supply Voltage ....................................................... 30V
Switch Output Voltage ............................................ 60V
Feedback Pin Voltage (Transient, 1ms) ................ ±15V
Storage Temperature Range ................ –65°C to 150°C
Operating Junction Temperature Range
Operating.............................................. 0°C to 100°C
Short Circuit ......................................... 0°C to 125°C
Lead Temperature (Soldering, 10 sec.)................ 300°C
W
U
/O
PACKAGE RDER I FOR ATIO
FRONT VIEW
ORDER PART
NUMBER
ORDER PART
5
4
3
2
1
V
V
IN
TOP VIEW
NUMBER
SW
V
V
1
2
3
4
5
6
7
8
9
20
19
V
V
SW
SW
GND
FB
LT1271CQ
LT1269CQ
LT1269CS
SW
NC
SW
18 NC
V
C
GND
GND
17 GND
16 GND
15 GND
14 GND
Q PACKAGE
5-LEAD PLASTIC DD
TJ MAX = 100°C, θJC = 4°C/W, θJA = 30°C/W*
POWER
SWITCH
POWER
SWITCH
GND
GND
FRONT VIEW
AGND
13
V
IN
ORDER PART
NUMBER
V
C
12 NC
11 NC
5
4
3
2
1
V
V
IN
FB 10
SW
GND
FB
SW PACKAGE
20-LEAD PLASTIC WIDE SO
LT1271CT
LT1269CT
V
C
θ WILL VARY FROM APPROXIMATELY 40°C/W
WITH 0.75 SQ. IN. OF 1 OZ. COPPER TO 46°C/W
T PACKAGE
5-LEAD PLASTIC TO-220
WITH 0.33 SQ. IN. OF 1 OZ. COPPER
TJ MAX = 100°C, θJC = 4°C/W, θJA = 50°C/W
*With device soldered to 1/2 square inch of 1oz copper over backside or internal layer
ground plane. Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS VIN = 15V, VC = 0.5V, VFB = VREF, switch pin open, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
Reference Voltage
Measured at Feedback Pin
V = 0.8V
C
1.224
1.214
1.244
1.244
1.264
1.274
V
V
REF
●
●
●
●
I
Feedback Input Current
V
= V
REF
350
4400
200
750
1100
nA
nA
B
FB
gm
Error Amplifier
Transconductance
∆I = ±25µA
C
3000
2400
6000
7000
µmho
µmho
Error Amplifier Source or
Sink Current
V = 1.5V
C
150
120
350
400
µA
µA
Error Amplifier Clamp
Voltage
Hi Clamp, V = 1V
1.8
0.25
2.3
0.52
V
V
FB
Lo Clamp, V = 1.5V
0.38
FB
Reference Voltage Line
Regulation
3V ≤ V ≤ V
V = 0.8V
●
●
0.03
%/V
IN
MAX, C
A
Error Amplifier Voltage Gain
Minimum Input Voltage (Note 3)
Supply Current
0.9V ≤ V ≤ 1.4V
500
800
2.8
7
V/V
V
V
C
3.0
10
I
3V ≤ V ≤ V
, V = 0.6V
C
mA
Q
IN
MAX
2
LT1271/LT1269
VIN = 15V, VC = 0.5V, VFB = VREF, switch pin open, unless otherwise noted.
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Control Pin Threshold
Duty Cycle = 0
0.7
0.5
0.9
1.08
1.25
V
V
●
●
Normal/Flyback Threshold
on Feedback Pin
0.4
0.45
16.3
6.8
0.54
V
V
V
Flyback Reference Voltage
I
= 50µA
FB
15
14
17.6
18
V
V
FB
FB
Change in Flyback
Reference Voltage
0.05 ≤ I ≤ 1mA
4.5
8.5
0.03
650
V
FB
Flyback Reference Voltage
Line Regulation
I
= 50µA
0.01
300
%/V
FB
3V ≤ V ≤ V
IN
MAX
Flyback Amplifier
∆I = ±10µA
C
150
µmho
Transconductance (gm)
Flyback Amplifier Source
and Sink Current
V = 0.6V
Source
Sink
●
●
15
25
32
40
70
70
µA
µA
C
I
= 50µA
FB
BV
Output Switch Breakdown
Voltage
3V ≤ V ≤ V
●
60
75
0.2
6.4
V
IN
MAX
I
= 1.5mA
SW
V
Output Switch (Note 1)
“On” Resistance
●
0.33
Ω
SAT
Control Voltage to Switch
Current Transconductance
A/V
I
Switch Current Limit (Note 2)
Duty Cycle = 50%
Duty Cycle = 80%
●
●
4
3.2
8
8
A
A
LIM
∆I
Supply Current Increase
During Switch On-Time
25
40
mA/A
IN
∆I
SW
f
Switching Frequency
LT1271
LT1269
●
●
50
85
60
100
70
115
kHz
kHz
DC (max)
Maximum Switch Duty Cycle
LT1271
LT1269
85
80
92
90
95
95
%
%
Flyback Sense Delay Time
1.5
µs
Shutdown Mode
Supply Current
3V ≤ V ≤ V
, V = 0.05V
C
100
400
µA
IN
MAX
Shutdown Mode
Threshold Voltage
3V ≤ V ≤ V
100
50
150
250
300
mV
mV
IN
MAX
●
The
temperature range.
Note 1: Measured with V in hi clamp, V = 0.8V.
●
denotes the specifications which apply over the full operating
Note 2: For duty cycles (DC) between 50% and 85%, minimum
guaranteed switch current is given by I = 2.67 (2 – DC).
LIM
Note 3: Minimum input voltage.
C
FB
3
LT1271/LT1269
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Switch Current Limit vs Duty Cycle
Switch Saturation Voltage
12
1.6
1.4
T = 25°C
J
1.2
1.0
0.8
0.6
0.4
0.2
0
9
–55°C
125°C
25°C
6
3
0
0
10 20 30 40 50 60 70
DUTY CYCLE (%)
90 100
0
1
80
2
3
4
5
SWITCH CURRENT (A)
1271/69 G01
1271/69 G02
U
O
TYPICAL APPLICATI S
Negative-to-Positive Buck-Boost Converter
L2
L1**
OPTIONAL
OUTPUT
FILTER
C3
100µH
D1
MBR340
V
V
IN
OUT
V
×
SW
12V, 1.5A
+
R1
C2
200µF
+
11.3k
C4*
LT1271
200µF
Q1
2N3906
OPTIONAL
INTPUT
FB
R3
V
C
GND
FILTER
R2
1.24k
2.2k
L3
C1
0.22µF
* REQUIRED IF INPUT LEADS ≥ 2"
** COILTRONICS CTX100-2-52
V
IN
×
–12V
1271/69 TA04
4
LT1271/LT1269
U
O
TYPICAL APPLICATI S
Boost Converter (5V to 12V)
5V
100µH*
V
IN
V
SW
FB
MBR330
12V
0.5A
LT1271
10.7k
+
V
GND
100µF
25V
C
1k
1.24k
1µF
1271/69 TA03
* COILTRONICS CTX100-2-52
U
PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
Q Package
5-Lead Plastic DD Pak
(LTC DWG # 05-08-1461)
0.060
(1.524)
TYP
0.390 – 0.415
(9.906 – 10.541)
0.060
0.256
0.165 – 0.180
(4.191 – 4.572)
(1.524)
(6.502)
0.045 – 0.055
(1.143 – 1.397)
15° TYP
+0.008
0.004
–0.004
0.060
(1.524)
0.183
(4.648)
0.059
(1.499)
TYP
0.330 – 0.370
(8.382 – 9.398)
+0.203
–0.102
0.102
(
)
0.095 – 0.115
(2.413 – 2.921)
0.075
(1.905)
0.057 – 0.077
(1.447 – 1.955)
0.050 ± 0.012
(1.270 ± 0.305)
0.300
(7.620)
0.013 – 0.023
(0.330 – 0.584)
+0.012
0.143
–0.020
0.028 – 0.038
(0.711 – 0.965)
+0.305
BOTTOM VIEW OF DD PAK
HATCHED AREA IS SOLDER PLATED
COPPER HEAT SINK
3.632
(
)
–0.508
Q(DD5) 0396
5
LT1271/LT1269
U
PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
T Package
5-Lead Plastic TO-220 (Standard)
(LTC DWG # 05-08-1421)
0.165 – 0.180
(4.191 – 4.572)
0.147 – 0.155
(3.734 – 3.937)
DIA
0.390 – 0.415
(9.906 – 10.541)
0.045 – 0.055
(1.143 – 1.397)
0.230 – 0.270
(5.842 – 6.858)
0.570 – 0.620
(14.478 – 15.748)
0.620
(15.75)
TYP
0.460 – 0.500
(11.684 – 12.700)
0.330 – 0.370
(8.382 – 9.398)
0.700 – 0.728
(17.78 – 18.491)
0.095 – 0.115
(2.413 – 2.921)
0.152 – 0.202
(3.861 – 5.131)
0.260 – 0.320
(6.60 – 8.13)
0.013 – 0.023
(0.330 – 0.584)
0.057 – 0.077
(1.448 – 1.956)
0.135 – 0.165
(3.429 – 4.191)
0.155 – 0.195
(3.937 – 4.953)
0.028 – 0.038
(0.711 – 0.965)
T5 (TO-220) 0398
6
LT1271/LT1269
U
PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
SW Package
20-Lead Plastic Small Outline (Wide 0.300)
(LTC DWG # 05-08-1620)
0.496 – 0.512*
(12.598 – 13.005)
19 18
16 14 13 12 11
20
17
15
0.394 – 0.419
(10.007 – 10.643)
NOTE 1
0.291 – 0.299**
(7.391 – 7.595)
2
3
5
7
8
9
10
1
4
6
0.037 – 0.045
(0.940 – 1.143)
0.093 – 0.104
(2.362 – 2.642)
0.010 – 0.029
(0.254 – 0.737)
× 45°
0° – 8° TYP
0.050
(1.270)
TYP
0.004 – 0.012
0.009 – 0.013
(0.102 – 0.305)
NOTE 1
0.016 – 0.050
(0.406 – 1.270)
(0.229 – 0.330)
0.014 – 0.019
S20 (WIDE) 0396
(0.356 – 0.482)
TYP
NOTE:
1. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS.
THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
7
LT1271/LT1269
TYPICAL APPLICATION
U
Negative Buck Converter
+
C2
100µF
D1
MBR735
LOAD
12k
R1
L1**
100µH
4.64k
V
IN
V
–5.2V AT 3.5A
×
SW
+
C3*
100µF
LT1271
Q1
2N3906
OPTIONAL
INTPUT
FILTER
FB
C
V
GND
OPTIONAL
OUTPUT
FILTER
+
C4
200µF
C1
R3
L3
10µH
R2
1.24k
L2
4µH
V
IN
×
–8V TO –30V
* REQUIRED IF INPUT LEADS ≥ 2"
1271/69 TA05
** COILTRONICS CTX100-2-52
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PART NUMBER
DESCRIPTION
COMMENTS
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500kHz, 1.5A Buck Switching Regulator
Good for V Up to 40V
IN
LT1370
6A, 42V Internal Switch
LT1371
3A, 42V Internal Switch, 90% Efficiency
Also Regulates Negative Flyback Outputs
LT1372
LT1374
V
V
Up to 25V, SO-8 Package
IN
IN
LT1376
Up to 25V, Uses 4.7µH Inductor
127169fb LT/TP 0798 2K REV B • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
8
●
●
LINEAR TECHNOLOGY CORPORATION 1992
(408)432-1900 FAX:(408)434-0507 www.linear-tech.com
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